Anyone who owns a Honda VFR 800 VTEC really should read the following. I have been dealing with this saga for a year and it finally appears the answer is at hand. The starter valves are not synced properly at either the factory or the dealer, plus the service manual is very misleading!

The improperly synced starter valves cause the engine to be much harder to control under some circumstances at smaller throttle openings.

I would like this stickied please as it may be some time before all VFR VTEC owners get the chance to review it.

Chumly has asked for this to be stickied for a while. I'll hold it stickied as long as some other VFR folks come forward and check in. Otherwise I'll leave it here for a month and then let it drop.

I suspect most VFR owners are also members of the VFR boards and the knowledge of this will get around pretty quick.

04-15-2005, 11:37 AM

Thumper 8

Quote:

Originally Posted by TeeTee

I suspect most VFR owners are also members of the VFR boards and the knowledge of this will get around pretty quick.

And of course, some of us don't have the problem either...

04-15-2005, 12:08 PM

Chumly

Hi Tony,
Iím glad you donít experience any problems and hope that none appear as time goes by. For many, the gestalt of riding conditions, such as the rider's style & roads dictate how noticeable these issues are.

I notice it a lot in part because I am often riding in low gears, with low throttle settings, light loads, and constantly changing speeds and RPM's, on narrow bumpy twisty roads.

04-15-2005, 01:24 PM

Thumper 8

Quote:

Originally Posted by Chumly

Hi Tony,
Iím glad you donít experience any problems and hope that none appear as time goes by. For many, the gestalt of riding conditions, such as the rider's style & roads dictate how noticeable these issues are.

I notice it a lot in part because I am often riding in low gears, with low throttle settings, light loads, and constantly changing speeds and RPM's, on narrow bumpy twisty roads.

I am up to 22,000 kms with no problems at all. Riding ranging from quick runs up to the Okanagan and beyond, 7 or 8 Duffey Lake loops and some very enthusiastic banzai runs through the twisties - all without any hiccups or hesitations and an always smooth and pleasing VTEC transition. I may be one of the lucky ones but my bike is stock except for my only mod - new Remus pipes ( :thumbup ), but the bike has been absolutely faultless with only the required basic maintenance for oil changes, new tires etc.

04-15-2005, 04:28 PM

Chumly

Hi Tony,

Part of the problem with positive assessments such as yours (and negative assessments such as mine) is that in isolation they are one person, subjective and somewhat arbitrary.

We would need to place our two bikes back to back in identical circumstances that exacerbate potential negative tenancies to see whether your bike performs differently than mine, at least in terms of our abilities and experience.

That is not to suggest that I would presume that your bike performs the same as mine and you donít notice it, but it does potentially eliminate a certain degree of subjectivity.

The other needed step in comparison analysis would be to compare starter valve sync differences and other measurable variables. Only then we would have a basis of comparison of both a subjective and objective nature.

This is being done as we speak in the UK by "Wiz", his cohorts, and Honda UK. It might be interesting to parallel their efforts here.

A classic example of the arbitrary element of what I am referring to is your reference to ďpleasing VTEC transitionĒ. I consider any noticeable transition due to the VTEC engagement to be distracting and unpleasing.

Another point of potential subjectivity is as mentioned the gestalt of riding conditions. The "fueling problems" experienced are not most prevalent under the circumstances you refer to ďquick runs up to the Okanagan and beyond, 7 or 8 Duffey Lake loops and some very enthusiastic banzai runs through the twistiesĒ but are most prevalent under the circumstances I refer to ďriding in low gears, with low throttle settings, light loads, and constantly changing speeds and RPM's, on narrow bumpy twisty roadsĒ. Two different environs, two different riding styles, two different sets of expectations.

The starter valve sync has no effect on VTEC engagement by the way. Nor does the starter valve sync likely have an effect on the lean-out part-throttle cruise surge problem. Given that you are running a non-stock exhaust does somewhat complicate a direct comparison.

04-15-2005, 04:59 PM

Thumper 8

[QUOTE=Chumly]
A classic example of the arbitrary element of what I am referring to is your reference to ďpleasing VTEC transitionĒ. I consider any noticeable transition due to the VTEC engagement to be distracting and unpleasing.
[QUOTE]

By pleasing, I mean smooth and strong - with the VTEC transition noticed by strong and smooth acceleration, and of course the change in exhaust note. There is no noticeable transition (ie, never any hesitation or abruptness or flat spot) and never has been, except for the smooth acceleration as the VTEC does its thing. I have been riding for 25 years +/-, and I have ridden plenty of crap bikes that sputter and misfire etc - the VFR has been faultless (although I would like an extra 20 or 30 hp!).

04-15-2005, 05:21 PM

Chumly

Hi Tony,
You may have misunderstood some of my points. The VTEC transition is not really at issue here, I referred to it to help illuminate the subjective versus objective nature of the VFR experience and how one might reduce the objective element. I am *not* arguing the merits or lack thereof of the VTEC transition.

04-19-2005, 01:22 PM

Sandworm

These same discussions have occurred with the previous '00 model VFR. With them it was the dynamics related to the O2 sensor. They all boiled down to the fact that the VFR, for all its greatness, is not a track bike.

What I have seen, and I think I am seeing again here, is a separation between those riders who own one bike that happens to be a VFR and those that own more than one bike. Those who live on their VFRs, like I did up until this year, have learned either consciously or unconsciously to minimize the unique nature of the VFR's throttle response. For them it has become a predictable and reliable part of the bike and is no longer noticed. Riders that alternate between bikes do not develop this as easily and I think that this is were the more difficult reviews of are coming from.

If I had a v-tec bike*, I would ride it for a month or two and leave my other bikes parked. If one constantly jumps between bikes, the differences only become sharper.

-Sandworm
*I would never purchase the current v-tec model, but that has more to do with my tastes in electrical systems than the v-tecs throttle response.

04-19-2005, 02:45 PM

Thumper 8

Quote:

Originally Posted by Sandworm

What I have seen, and I think I am seeing again here, is a separation between those riders who own one bike that happens to be a VFR and those that own more than one bike. Those who live on their VFRs, like I did up until this year, have learned either consciously or unconsciously to minimize the unique nature of the VFR's throttle response. For them it has become a predictable and reliable part of the bike and is no longer noticed. Riders that alternate between bikes do not develop this as easily and I think that this is were the more difficult reviews of are coming from.

-Sandworm

Good point. I rode an RC 51 before the VFR, and the throttle response on the RC seemed a little 'sharper' and obviously the power was more linear, but when I got on the VFR, the throttle response did not seem too different or out of place. I have ridden other bikes where the throttle response is much different from the throttle of the RC and VFR. Only one bike now, so no direct comparisons.

04-19-2005, 08:31 PM

Chumly

Quote:

Originally Posted by Sandworm

What I have seen, and I think I am seeing again here, is a separation between those riders who own one bike that happens to be a VFR and those that own more than one bike.

Interesting Master Worms, but in this specific case it strongly appears that the SVís are quite often not well synced and hence exacerbate part throttle tractability, all other perspectives aside.

04-19-2005, 08:48 PM

benjamin

I have to add I have ridden R1 but when I'm on my VFR I feel like I can fly.

04-29-2005, 12:45 AM

rubberhead

Quote:

Originally Posted by TeeTee

I suspect most VFR owners are also members of the VFR boards and the knowledge of this will get around pretty quick.

Can someone post URLs to these boards please?

04-29-2005, 01:26 AM

nutcracker

I red that article about a month ago , very interesting . This is my first fuel injected bike so I'm not really sure how it's suppose to respond at steady slow speed but I think that it does act kinda weird. I would really like to compare to another VFR,

04-29-2005, 10:21 AM

Chumly

Quote:

Originally Posted by rubberhead

Can someone post URLs to these boards please?

The really good news is that a Starter Valve Sync solves some /most/all of the issues people complain about.

These threads do ramble and go off on many tangents. The essential point now is that the Starter Valves are rarely in sync, the dealers donít do it so you need to go with a Morgan Carbtune. Also there is an outstanding issue in that the Shop Manual is very likely to be incorrect/incomplete.

I support ďWizĒ and all his posts with the possible exception of the interpretation of the shop manual's Starter Valves settings. I would want Honda Japan to comment on the Shop Manual, but they have not.

The O2 Sensor Swap has turned out to be a red herring from the perspective of Honda Japan. They officially have said that none of bikes are wired around the wrong way. That does not mean that O2 Sensor Swap does not have an effect, it can force the EFI into open loop operation.

I red that article about a month ago , very interesting . This is my first fuel injected bike so I'm not really sure how it's suppose to respond at steady slow speed but I think that it does act kinda weird. I would really like to compare to another VFR,

PM me and we'll see :)

05-18-2005, 01:43 PM

Chumly

I had a nice chat with Jeff at Honda Canada (I asked the same question this time last year). I was told that the Honda Canada Technicianís official position is that they recognize that there are certain "characteristics" that the motor may have, such as the VTEC engagement, off idle sharpness, and steady throttle surge but that these "characteristics" are "normal" for the bike, and they have no plans at this time to do anything about, but that the Honda Canada Technicianís have logged my concerns and that they have received other logged input from other owners with similar concerns.

Jeff at Honda Canada said he very much doubted that there is anything wrong with any of the ECUís. He went on to say much the same as last year; that Honda is meeting very tight future emission standards, while producing very high performance engines, and that it is a difficult balancing act.

Jeff did say that the use of premium gas in Canada has an additive that can coat the 02 sensors and make them lazy or ineffective, and that may be a cause for some problems. I told him that the 02 sensors only contribute in the limited conditions of steady state closed loop cruising, so as to lean out the mixture, and that ineffective 02 sensors would not affect performance under constantly changing throttle inputs as the EFI does not go into closed loop unless it is steady state throttle.

I have a PC III and O2 elims and did a really precise SV sync as well as remove all slack from the throttle cables. My bike is better but does not equal the linear throttle of many other bikes.

From what I can tell you are saying that removing PAIR will have no effect if O2 elims are in place. Perhaps that’s why I never notified any improvement when I disabled PAIR, so I left PAIR enabled but…….are you aware that the O2 sensors do absolutely nothing most of the time, and only come into effect during closed loop, steady state, steady throttle cruising operation and not at other times? The O2 sensors on the VTEC do not act as they do in a modern auto engine where they are relied on much more often. Also the VFR ECU is not a “learning” ECU.

I get the impression from your posts on VFRD that you might believe the O2 sensors are enabled (i.e. closed loop) much more often than is the case (as is the case with modern auto engines.

03-18-2007, 07:54 PM

steve tech

Quote:

Originally Posted by Chumly

I have a PC III and O2 elims and did a really precise SV sync as well as remove all slack from the throttle cables. My bike is better but does not equal the linear throttle of many other bikes.

From what I can tell you are saying that removing PAIR will have no effect if O2 elims are in place. Perhaps thatís why I never notified any improvement when I disabled PAIR, so I left PAIR enabled butÖÖ.are you aware that the O2 sensors do absolutely nothing most of the time, and only come into effect during closed loop, steady state, steady throttle cruising operation and not at other times? The O2 sensors on the VTEC do not act as they do in a modern auto engine where they are relied on much more often. Also the VFR ECU is not a ďlearningĒ ECU.

I get the impression from your posts on VFRD that you might believe the O2 sensors are enabled (i.e. closed loop) much more often than is the case (as is the case with modern auto engines.

First let me say Hi and thanks for the reply.
A little bit about myself, I have been a tech, working for BMW (cars) for the past 35 years. I have owned this 05 VFR for just over a year This year I got to thinking that I should be able to get the thing to be a bit more smooth on take off than it is. It is awesome on the highway etc but it really is hard work around town. Anyway this is why I am experimenting and asking questions.
I was not aware that the o2 sensors only work in closed loop at certain times.
I have never heard of this on any ECU cat system that I have come across before as for the cat to function properly the engine has to run in closed loop all the time. I will monitor the o2 sensors while riding to see what happens!
Today I got out and tried the bike for a good long ride with the pair valve blocked. The response from closed throttle at slow speeds is a lot better however the throttle is still jerky at say 3000 in second when riding along on a steady throttle (if that makes sense)
Also I thought that on deceleration without the pair valve that the mixture would be rich in the cat and I verified that as I get a sulphur smell when going down hill with throttle closed.
From this you can say that if the pair valve is to be disabled for any length
of time the cat would have to be removed. If not I can't see it lasting too long. Honda it looks like add additional air from the pair system to pass emisions on deceleration. To me right now it looks like we would have to remove the cat, add the resistors, remove the pair, sync the starter valves and remap using a pc III. It looks like you are almost at that point anyway:laughing
I am going to install a lot of test equipment and try to see whats happening?
I don't see why it's the way it is, alright the vstrom I had was not as highly tuned, the Ducati ST3 is a v twin, but the speed triple is highly tuned and passes emisions AND the mapping is spot on!

03-18-2007, 09:27 PM

Chumly

Nice to make your acquaintance!

I assure you the engine management system does not run in closed loop unless it’s steady-state-cruise-steady-throttle. The rest of time the ECU runs in open loop and the O2 sensors are not used, the ECU and then relies on the various other "inputs" such as TPS and of course the OEM map. Note the PCIII does not change the OEM map as the PCIII is after the ECU.

A lot of people on VFRD have done a cat-ectomy, also FWIW I have not heard of people with failed or overheating cats from PAIR disabling.

I have talked extensively with Honda Canada and the top whizzes on VFRD I own the shop manual and have an OK background in this stuff but I don't make a living at it like you, alas. BTW the reason Honda did this silly stuff was to meet emissions regulations not in place yet (I cannot recall the standard but it's CARB 2010 compliant or some such).

I truly welcome any ideas and input you have on making the throttle action more linear.

03-18-2007, 10:55 PM

steve tech

Quote:

Originally Posted by Chumly

Nice to make your acquaintance!

I assure you the engine management system does not run in closed loop unless itís steady-state-cruise-steady-throttle. The rest of time the ECU runs in open loop and the O2 sensors are not used, the ECU and then relies on the various other "inputs" such as TPS and of course the OEM map. Note the PCIII does not change the OEM map as the PCIII is after the ECU.

A lot of people on VFRD have done a cat-ectomy, also FWIW I have not heard of people with failed or overheating cats from PAIR disabling.

I have talked extensively with Honda Canada and the top whizzes on VFRD I own the shop manual and have an OK background in this stuff but I don't make a living at it like you, alas. BTW the reason Honda did this silly stuff was to meet emissions regulations not in place yet (I cannot recall the standard but it's CARB 2010 compliant or some such).

I truly welcome any ideas and input you have on making the throttle action more linear.

Maybe let me know where you heard about the closed/open loop steady throttle deal. I have never heard of this, especially if they are trying to meet CARB standards. If this was the case then disconnecting the PAIR system or removing the o2 sensor connections would not make the slightest difference as the only time the bike would be in closed loop would be when none of these issues we are having are taking place.

03-19-2007, 01:32 PM

Chumly

There are six main things that can exacerbate VFR throttle problems:

1) At very low throttle openings if the SV's are not synced.

2) At steady state when the ECU goes into closed loop the EFI fuel ratio wants to go stoichiometric and thus you can have lean surging.

3) While spinning up through the VTEC transition @ 6,800 RPM (this changed on the ‘05’s but I’ll not bother talking about that here) there is a stumble then a hit due to the abrupt opening of the extra valves. This is most notable at smaller throttle openings at lower engine loads when transitioning slowly up and down repeatedly through the VTEC transition.

4) At some throttle openings and gear positions etc the EFI maps too lean for smoothest performance (this one is somewhat contentious but if you look at the maps of people’s VFR's before and after proper dyno tuning the end results are most often a higher F/A at some given settings, so I give it credence and hey Dynojet thinks most modern bike EFI's are too lean at certain operational points).

5) There is some argument that the VFR VTEC’s engine management system does not work as well as some other bikes, and if you check the 05’s on up they have made some changes such as a different (finer) injector, altered the VTEC engagement RPM, staggered the VTEC engagement/disengagement RPM's, and altered the EFI map - maybe other stuff too but that’s all I know of related to the engine management system. Understandably this one is also somewhat contentious and I do not give it as much credence as the general map leanness viewpoint because some other brands of bikes appear to have EFI systems no more (and perhaps less sophisticated) than the 6th gen on up to the ‘04’s, but OTOH you would need to ask why Honda made these tuning changes if there were no issues related to this argument. There have not been a lot of 05’s on up sold as of yet to get a picture, but the consensus so far seems to be that the engines are more tractable and more predictable.

6) Throttle cable slack.

In answer to your question about my sources I have already listed them in my first post and in subsequent posts to you and others as discussed.

I forgot to mention I also had a number of chats with the fine people at Dynojet. I would not say they were experts with the VFR VTEC’s idiosyncrasies but they are a wealth of general tuning information. Remember I said I cannot recall the future emissions standard the VFR was targeted for........I could find out. You sound about the same age as me; perhaps we can meet up and go for a spin and a beverage sometime.

Cheers,
Dan

03-19-2007, 07:26 PM

steve tech

Quote:

Originally Posted by Chumly

There are six main things that can exacerbate VFR throttle problems:

1) At very low throttle openings if the SV's are not synced.

2) At steady state when the ECU goes into closed loop the EFI fuel ratio wants to go stoichiometric and thus you can have lean surging.

3) While spinning up through the VTEC transition @ 6,800 RPM (this changed on the Ď05ís but Iíll not bother talking about that here) there is a stumble then a hit due to the abrupt opening of the extra valves. This is most notable at smaller throttle openings at lower engine loads when transitioning slowly up and down repeatedly through the VTEC transition.

4) At some throttle openings and gear positions etc the EFI maps too lean for smoothest performance (this one is somewhat contentious but if you look at the maps of peopleís VFR's before and after proper dyno tuning the end results are most often a higher F/A at some given settings, so I give it credence and hey Dynojet thinks most modern bike EFI's are too lean at certain operational points).

5) There is some argument that the VFR VTECís engine management system does not work as well as some other bikes, and if you check the 05ís on up they have made some changes such as a different (finer) injector, altered the VTEC engagement RPM, staggered the VTEC engagement/disengagement RPM's, and altered the EFI map - maybe other stuff too but thatís all I know of related to the engine management system. Understandably this one is also somewhat contentious and I do not give it as much credence as the general map leanness viewpoint because some other brands of bikes appear to have EFI systems no more (and perhaps less sophisticated) than the 6th gen on up to the Ď04ís, but OTOH you would need to ask why Honda made these tuning changes if there were no issues related to this argument. There have not been a lot of 05ís on up sold as of yet to get a picture, but the consensus so far seems to be that the engines are more tractable and more predictable.

6) Throttle cable slack.

In answer to your question about my sources I have already listed them in my first post and in subsequent posts to you and others as discussed.

I forgot to mention I also had a number of chats with the fine people at Dynojet. I would not say they were experts with the VFR VTECís idiosyncrasies but they are a wealth of general tuning information. Remember I said I cannot recall the future emissions standard the VFR was targeted for........I could find out. You sound about the same age as me; perhaps we can meet up and go for a spin and a beverage sometime.

Cheers,
Dan

Sounds good, I will take you up on that!
My bike is an 05, so I don't think they have achieved much.
I'm originally from the UK so I always pick up BIKE magazine, its ironic but this months tests the VFR against the BMW 800. They really pick fault with the "snatchy" throttle the VFR has and even write an article about what happened to your wonderful engine Honda?
I will bring my bike into the shop at work one day and measure the emissions and do some experimenting with the o2 sensors.
If you pm me your email I will scan the article and send it you if you wish.

03-19-2007, 09:11 PM

Chumly

I would like to read that article sure! Iíve pmíd you

Does your bike have the clear turn signal lenses? If so that hopefully will confirm it has the latest changes I talked about such as the different (finer) injectors, altered VTEC engagement RPM, staggered VTEC engagement/disengagement RPM's, and altered the EFI map.

Donít get me wrong I still think itís a nice bike. I was going to sell mine but after all the farting around getting it running decently I canít really find anything I like that much more to warrant all the hassles of selling and buying.

Then I made a mistake in that the most recent engine management changes I talked about start with the '06 model year. Sometimes it’s hard to remember all the trivia associated with VFR’s. Back to watching South Park!

03-24-2007, 03:22 AM

Chumly

Hi-yah Steve,

You might be interested in what’s happening with the 2nd generation Yamaha FZ1. It too is plagued with EFI problems, but because it’s a much better supported bike in the after-market (Ivan etc) there are now solutions which we cannot get for our VFR VTEC’s. In particular a Fuel Cutoff Eliminator is unavailable for the VFR VTEC.

My prediction is that the next 5 years are going to see more and more bikes with emissions regulations EFI issues.

On an efi engine, tickover fuelling is handled by injectors, but the engineers turn them off on closed-throttle coasting. Nobody should notice because the throttle is shut – so the rider won’t care – and there’s less fuel, unburned or otherwise, in the exhaust mixture.

But if you cut off fuel to an engine spinning at, say, 5000rpm (with pistons whizzing up and down 40 times per half second), the motor purges itself of fuel (in fact an efi motor purges itself of everything – with the throttle closed there’s no air either, which creates a vacuum, a problem in itself).

So now the inlet tracts and combustion chamber of the efi engine are ‘dry’. Which is okay if you keep the throttle closed and run the engine down to tickover – the injectors just switch back on again to keep the motor running. But what happens if the rider opens the throttle again before that point?

Engineers call this process ‘fuel reinstatement’. The rider twists the throttle and the bike’s ECU reads this, telling the injectors to deliver fuel into the air-stream in the throttle bodies.

At the same time, a butterfly valve in the throttle bodies opens, allowing air into the inlet tracts (the ECU also opens secondary butterfly valves – slowly – using a servo, to control the transition from closed throttle to open throttle).

So fuel is squirted from the injectors and the butterfly valves are partly open to let air into the engine.

But because the motor is completely fuel-less, the new fuel has to travel the length of the inlet tracts and into the combustion chamber before it can burn. It’s not a big distance, but it’s far enough to introduce a delay between opening the throttle and getting a response.

Also, some fuel from the initial injection is drawn out of the fuel/air mixture and re-lines, or ‘wets’, the walls of the inlet tracts, adding further delay in the petrol reaching the cylinder.

The cumulative effect is called the ‘fuel transport time’ – and the longer that is, the worse the throttle snatch.

03-24-2007, 04:03 PM

steve tech

Quote:

Originally Posted by Chumly

Hi-yah Steve,

You might be interested in whatís happening with the 2nd generation Yamaha FZ1. It too is plagued with EFI problems, but because itís a much better supported bike in the after-market (Ivan etc) there are now solutions which we cannot get for our VFR VTECís. In particular a Fuel Cutoff Eliminator is unavailable for the VFR VTEC.

My prediction is that the next 5 years are going to see more and more bikes with emissions regulations EFI issues.

Yeh thats the same mag. I got the VFR issue out of I sent you.
Just finished syncing my starter valves. I also adjusted the chain at the same time (never done it yet so figured it's about time)
By the way I checked the pair valve while I was at it, its open unless powered closed on throttle shut off. I did some experiments with the pair on and off while monitoring the mercury tubes. There is quite a difference between the measurements with the pair plugged or not. If you are running the pair I would sync the starter valves with it connected. If your going to plug it then sync the starter valves with it plugged. I know thats not the "Honda" way but there is quite a difference in the back pressure between the front 2 and the rear cyls. With regard to the throttle switch I am experimenting also to find when fuel cut off takes place on the Honda. The VFR has a potentiometer for a tp sensor so it would be easy enough to build iin a circuit so it never sees idle at throttle shut off at higher rpm or road speed. Thats all the guy did to fix the Yam. Ive done it before on cars.
By the way the tp sensor is part of the throttle assembly so you dont want to Fxxx it up!! Right now I have the pair valve working again and will try the bike when the rain stops (if ever). It dosn't take very long to do the starter valves so I will see what has transpired with this adjustment first.
Steve
.

03-24-2007, 11:26 PM

Chumly

I synced the SV’s the way Honda recommends in the shop manual, I can’t remember if that meant with the PAIR disabled or enabled, as that was two years ago now.

I would really like to know the exact RPM fuel cutoff takes place, and also if it matters what gear it’s in, and also if it matters what speed you are going.

I know the TPS is a pot and you could add or subtract resistance by either putting a resistor in series or one in parallel (whichever is required I’m not sure). I am an Electrician so I know RLC resistance / inductance / capacitance circuits.

What I’m wondering though, is that by changing the effective overall TPS resistance so the ECU never thinks the bike has the throttle fully closed, you are in essence throwing the TPS out of sync. That would mean the EFI pulse width would be longer at all throttle positions (expect full throttle) and would make all F/A settings a bit richer. Wouldn’t it?

I brought this up on VFRD http://www.vfrdiscussion.com/forum/index.php? but no one seemed to know and no one I have ever talked anywhere else has tested for fuel cutoff or tried to defeat fuel cutoff. AFAICT you are the first to look into VFR fuel cutoff. I did ask Ivan's Rockland County Motorcycle and he said he did not know and has no plans for the VFR.

Great stuff man, and it sounds like you could get cool results that would make the VFR easier to operate. The question is: does the VFR use fuel cutoff to minimize emissions?

03-25-2007, 12:54 AM

steve tech

I have not gone in to it yet but a simpler way maybe is to remove the road speed signal at the engine ecu. I have only got the wiring diagram for the non abs model (mines abs) however it looks like the speed signal is hard wired to the speedo, engine ecu and abs cu separately (no can bus) if this is the case it would be easier enough to try. I wouldnt think it would set a fault because it is a normal situation (bike at standstill). If Honda use fuel shut off, that would explain the issue of the sharp turn while moving irritating throttle snatch I get.
Twice on my commute going downhill braking and turning right quite sharply. Also the irritating snatchy throttle going over bumps on decel.
First things first though I have to find if they use throttle shut off!
By the way, looking at the way the idle increases with the pair connected it shows that the pair system is actually helping to overcome the back pressure of the cat/exhaust system and speed the exhaust gas's out.

Lots of engine decel here!! No jerkyness, maybe we are NOT Freddy Spencer!!

03-27-2007, 01:44 AM

Chumly

Go Freddy!

Assuming the road speed signal can be deleted from the engine ECU without causing problems, why would stopping this signal would stop fuel shut-off? I would have thought RPM and TPS are the two variables needed for fuel-shut off.

With the FZ1 RPM @ 4,500 and over plus closed TPS signal enables fuel-shut off. I don’t think road speed signal is part of fuel shut-off logic, but I could be wrong. BTW Ivan’s FZ1 Fuel Cut-off Eliminator is a small tube with 6 wires.

03-27-2007, 08:45 PM

steve tech

Quote:

Originally Posted by Chumly

Go Freddy!

Assuming the road speed signal can be deleted from the engine ECU without causing problems, why would stopping this signal would stop fuel shut-off? I would have thought RPM and TPS are the two variables needed for fuel-shut off.

With the FZ1 RPM @ 4,500 and over plus closed TPS signal enables fuel-shut off. I donít think road speed signal is part of fuel shut-off logic, but I could be wrong. BTW Ivanís FZ1 Fuel Cut-off Eliminator is a small tube with 6 wires.

I don't know about Honda but BMW only cuts fuel with a road speed signal.
Anyway the main thing is my VFR is awesome now the starter valves are synced. I rode for 5 hours last Sunday (actually came out your way).
The bike runs great with no snatch at any time, I rode to work today in traffic and it's a different beast!
As I said I synced them with the pair working also making sure that as I opened up the throttle all cyls where pulling the same. I also adjusted the chain. I am running the idle at 1500 with the pair connected.
If I had adjusted them with the pair blocked off as in the book then when it's connected back they would have been a mile out! Try it you will see how far out they are. With the manometer connected set them with your thumb over the pair hose (air cleaner connector) then remove your thumb, the revs will increase and the gauges will be way out!

03-27-2007, 10:36 PM

Thumper 8

Quote:

Originally Posted by steve tech

Anyway the main thing is my VFR is awesome now the starter valves are synced. I rode for 5 hours last Sunday (actually came out your way).
The bike runs great with no snatch at any time, I rode to work today in traffic and it's a different beast!

Hmmm, I think both your bikes are essentially stock - except for the fiddling and adjustments noted in this thread. I am fortunate but I have never had any noticeable lag, no real flat spot around 5,000 to 6,000 rpm and always a very smooth VTEC transition. All I have done, besides basic maintenance, is tighten my throttle cable a couple of times to remove any annoying slack and put on Remus CF pipes (cat back set up) which seems to give the bike a little extra mid-range oomph - strictly seat of the pants impression though. Now you have got me wondering if I can make a good bike even better... or should I stick with the old 'if it ain't broke don't fix it' philosophy? I have ridden one other 6th gen VFR and it seemed a little 'jerkier' than mine - a little harder to ride smoothly and it seemed to have a slower throttle response, but all this talk of improving an already great bike has got me wondering. One day I may want to hook up with you guys and compare notes - and see if it is worth fiddling with the bike to get even better performance.

03-28-2007, 12:31 AM

Chumly

Hi-yah Steve,
The VFR engine management system is nowhere near as sophisticated as modern autos, Honda’s system would be much more akin to the FZ1 (minus VTEC of course), that’s pretty bare-bones-basic by auto standards. I'm taking a decent guess that if the FZ1 ECU needs RPM data for fuel cut-off, so would the VFR's ECU.

The last time I synced the SV’s was two years ago and I did get them nice and even at idle, but I seem to recall they did not run even off idle. Maybe I should try and sync the SV’s with PAIR enabled and off idle too.

Did you try syncing the SV’s with PAIR disabled as per the manual to see if it made things better or worse?

I have confirmed that the SV’s can go out of sync easily and it takes many km's before they “settle down”.

Hey Thumps,
You might be a happier rider by following these suggestions, shops don’t do this kind of stuff with a routine service. For me this is the first bike engine I was not real happy with out-of-the-box, and I don’t breathe on gear unless it bugs me. Like Steve pointed out, Bike mag agrees about the VFR being wacky.

Colbert Report's on, gotta go!

03-28-2007, 09:09 AM

J1k

kinda off the topic but has anyone had issues with valves being out of adjustment?iam curious as i work on these things alot and have run into many that are out.i keep hearing that they rarely go out but iam finding alot are tight and its always on the 05/06's.

03-28-2007, 01:36 PM

Chumly

I’ve heard the same things as you that they hold their clearances well. How exactly are you checking them; I am sure you know getting the correct “feel” can be rather subjective.

03-28-2007, 06:07 PM

Thumper 8

Quote:

Originally Posted by J1k

kinda off the topic but has anyone had issues with valves being out of adjustment?iam curious as i work on these things alot and have run into many that are out.i keep hearing that they rarely go out but iam finding alot are tight and its always on the 05/06's.

My '02 has 53,000 kms now - I have had two valve inspections done - both times no adjustment needed.

03-28-2007, 09:09 PM

steve tech

Quote:

Originally Posted by Thumper 8

Hmmm, I think both your bikes are essentially stock - except for the fiddling and adjustments noted in this thread. I am fortunate but I have never had any noticeable lag, no real flat spot around 5,000 to 6,000 rpm and always a very smooth VTEC transition. All I have done, besides basic maintenance, is tighten my throttle cable a couple of times to remove any annoying slack and put on Remus CF pipes (cat back set up) which seems to give the bike a little extra mid-range oomph - strictly seat of the pants impression though. Now you have got me wondering if I can make a good bike even better... or should I stick with the old 'if it ain't broke don't fix it' philosophy? I have ridden one other 6th gen VFR and it seemed a little 'jerkier' than mine - a little harder to ride smoothly and it seemed to have a slower throttle response, but all this talk of improving an already great bike has got me wondering. One day I may want to hook up with you guys and compare notes - and see if it is worth fiddling with the bike to get even better performance.

Hi, I'm the kind of guy that thinks if its not broken don't fix it!!
I got involved in this because like Dan this is the first bike that Ive owned that I thought was a pain to ride around town.
I think it depends on your mechanical ability, if you really understand how it works and what your doing then go for it. If not you may end up with it being worse.